Adhesive film and method for manufacturing electronic device

ABSTRACT

An adhesive film includes a base material layer; an adhesive resin layer (A) provided on a first surface side of the base material layer; and an adhesive resin layer (B) provided on a second surface side of the base material layer and in which an adhesive force is decreased by an external stimulus, in which, as measured by method 1, an integrated tacking force value (F2.5) of the adhesive resin layer (B) is 1.0 gf/sec or more at a test speed of 2.5 mm/min and a test temperature of 130° C., and an integrated tacking force value (F30) of the adhesive resin layer (B) is 7.0 gf/sec or more at a test speed of 30 mm/min and a test temperature of 130° C.

TECHNICAL FIELD

The present invention relates to an adhesive film and a method formanufacturing an electronic device.

BACKGROUND ART

As a technology which is able to reduce the size and weight ofelectronic devices (for example, semiconductor apparatuses), a fan-outtype WLP (wafer level package) is being developed.

In an eWLB (Embedded Wafer Level Ball Grid Array), which is one of themethods for manufacturing a fan-out type WLP, it is possible to adopt amethod in which a plurality of electronic components such assemiconductor chips are temporarily fixed in a separated state on anadhesive film attached to a support substrate, and the plurality ofelectronic components are sealed in a batch with a sealing material.Here, the adhesive film needs to be fixed to the electronic componentand the support substrate in the sealing step or the like and needs tobe removed from the sealed electronic component and the supportsubstrate after the sealing.

Examples of a technique related to such a fan-out type WLP manufacturingmethod include the technique described in Patent Document 1 (JapanesePatent Laid-Open No. 2011-134811).

Patent Document 1 discloses a heat-resistant adhesive sheet formanufacturing a semiconductor apparatus, which is used by being attachedwhen resin-sealing a substrateless semiconductor chip, in which the heatresistant adhesive sheet has a base material layer and an adhesivelayer, the adhesive layer has an adhesive force to SUS304 after bondingof 0.5 N/20 mm or more, is cured by a stimulus received until thecompletion of a resin sealing step, and has a peel force with respect toa package of 2.0 N/20 mm or less.

RELATED DOCUMENT Patent Document

-   [Patent Document 1] Japanese Patent Laid-Open No. 2011-134811

SUMMARY OF THE INVENTION Technical Problem

According to studies by the inventors of the present invention, it isclear that, when an electronic component is arranged on an adhesive filmand the electronic component is sealed with a sealing material, aposition of the electronic component may be shifted (also referred tobelow as position shifting of the electronic component).

The present invention was made in view of the above circumstances andprovides an adhesive film capable of suppressing position shifting ofelectronic components in a sealing step.

Solution to Problem

The inventors of the present invention carried out intensive studies inorder to achieve the above object. As a result, it was found that, in anadhesive film provided with a base material layer, an adhesive resinlayer (A) provided on a first surface side of the base material layer,and an adhesive resin layer (B) provided on a second surface side of thebase material layer and in which an adhesive force is decreased by anexternal stimulus, in which measuring an integrated value of the tackingforce of the adhesive resin layer (B), which is measured by a specificmethod, is effective as a design guideline for an adhesive film forsuppressing the position shifting of an electronic component in asealing step, thereby completing the present invention.

According to the present invention, an adhesive film and a method formanufacturing an electronic device illustrated below are provided.

-   -   [1]        -   An adhesive film including a base material layer,        -   an adhesive resin layer (A) provided on a first surface side            of the base material layer,        -   and an adhesive resin layer (B) provided on a second surface            side of the base material layer and in which an adhesive            force is decreased by an external stimulus,        -   in which, as measured by method 1, an integrated tacking            force value (F_(2.5)) of the adhesive resin layer (B) is 1.0            gf/sec or more at a test speed of 2.5 mm/min and a test            temperature of 130° C., and an integrated tacking force            value (F₃₀) of the adhesive resin layer (B) is 7.0 gf/sec or            more at a test speed of 30 mm/min and a test temperature of            130° C.,        -   (method 1) using a tacking tester, a probe is pressed on the            adhesive resin layer (B) for 60 seconds under conditions of            a probe load of 100 gf and a probe pushing speed of 120            mm/min, then, at a test temperature of 130° C., tack            strengths (gf) are respectively measured at test speeds of            2.5 mm/min and 30 mm/min, measurement time is set as a            horizontal axis and the tack strength (gf) is set as a            vertical axis, integrated values are each calculated from a            point where the tack strength starts to rise from 0 to a            point where the tack strength becomes 0 again, and the            calculated values are respectively set as F_(2.5) and F₃₀.    -   [2]        -   The adhesive film according to [1],        -   in which the adhesive film is used for temporarily fixing an            electronic component when the electronic component is sealed            with a sealing material in an electronic device            manufacturing step.    -   [3]        -   The adhesive film according to [1] or [2],        -   in which an adhesive force of the adhesive resin layer (B)            is decreased by heating at a temperature over 150° C.    -   [4]        -   The adhesive film according to [3], in which the adhesive            resin layer (B) includes at least one selected from a gas            generating component and a heat-expandable microsphere.    -   [5]        -   The adhesive film according to any one of [1] to [4],        -   in which a content of at least one selected from a gas            generating components and a heat-expandable microsphere in            the adhesive resin layer (A) is 0.1% by mass or less when an            entire adhesive resin layer (A) is 100% by mass.    -   [6]        -   The adhesive film according to any one of [1] to [5],        -   in which the adhesive resin layer (A) includes a            (meth)acrylic adhesive resin.    -   [7]        -   A method for manufacturing an electronic device including at            least:        -   a step (1) of preparing a structure having the adhesive film            according to any one of [1] to [6], an electronic component            attached to the adhesive resin layer (A) of the adhesive            film, and a support substrate attached to the adhesive resin            layer (B) of the adhesive film;        -   a step (2) of sealing the electronic component with a            sealing material;        -   a step (3) of peeling the support substrate from the            structure by decreasing an adhesive force of the adhesive            resin layer (B) by applying an external stimulus;        -   and a step (4) of peeling the adhesive film from the            electronic component.    -   [8]        -   The method for manufacturing an electronic device according            to    -   [7],        -   in which the sealing material is an epoxy resin-based            sealing material.

Advantageous Effects of Invention

According to the present invention, it is possible to provide anadhesive film capable of suppressing position shifting of electroniccomponents in a sealing step.

BRIEF DESCRIPTION OF THE DRAWINGS

The object described above and other objects, features, and advantageswill be further clarified by the preferable embodiments described belowand the accompanying drawings below.

FIG. 1 is a cross-sectional view schematically showing an example of astructure of an adhesive film of an embodiment according to the presentinvention.

FIG. 2 is a cross-sectional view schematically showing an example of amethod for manufacturing an electronic device of an embodiment accordingto the present invention.

FIG. 3 is a cross-sectional view schematically showing an example of amethod for manufacturing an electronic device of an embodiment accordingto the present invention.

DESCRIPTION OF EMBODIMENTS

A description will be given below of embodiments of the presentinvention with reference to the drawings. In all the drawings, commonreference numerals are given to the same constituent components anddescription thereof will not be appropriately repeated. In addition, thefigures are schematic views and do not match the actual dimensionalratios. In addition, unless otherwise specified, “A to B” in thenumerical range represents A or more and B or less. In addition, in thepresent embodiment, “(meth) acrylic” means acrylic, methacrylic, or bothacrylic and methacrylic.

1. Adhesive Film

A description will be given below of an adhesive film 50 according tothe present embodiment.

FIG. 1 is a cross-sectional view schematically showing an example of thestructure of the adhesive film 50 of the embodiment according to thepresent invention.

As shown in FIG. 1 , the adhesive film 50 according to the presentembodiment is provided with a base material layer 10, an adhesive resinlayer (A) provided on a first surface 10A side of the base materiallayer 10, and an adhesive resin layer (B) provided on a second surface10B side of the base material layer 10 and in which an adhesive force isdecreased by an external stimulus, in which, as measured by method 1, anintegrated tacking force value (F_(2.5)) of the adhesive resin layer (B)is 1.0 gf/sec or more at a test speed of 2.5 mm/min and a testtemperature of 130° C., and an integrated tacking force value (F₃₀) ofthe adhesive resin layer (B) is 7.0 gf/sec or more at a test speed of 30mm/min and a test temperature of 130° C.

(Method 1) Using a tacking tester, a probe is pressed on the adhesiveresin layer (B) for 60 seconds under conditions of a probe load of 100gf and a probe pushing speed of 120 mm/min, then, at a test temperatureof 130° C., tack strengths (gf) are respectively measured at test speedsof 2.5 mm/min and 30 mm/min, measurement time is set as a horizontalaxis and the tack strength (gf) is set as a vertical axis, integratedvalues are each calculated from a point where the tack strength startsto rise from 0 to a point where the tack strength becomes 0 again, andthe calculated values are respectively set as F_(2.5) and F₃₀.

As described above, according to studies by the inventors of the presentinvention, it is clear that, when an electronic component is arranged onan adhesive film and the electronic component is sealed with a sealingmaterial, the position of the electronic component may be shifted.

The inventors of the present invention carried out extensive studies inorder to realize an adhesive film which is able to suppress positionshifting of electronic components in the sealing step. As a result, itwas found for the first time that, in the adhesive film 50 provided withthe base material layer 10, the adhesive resin layer (A) provided on thefirst surface 10A side of the base material layer 10, and the adhesiveresin layer (B) provided on the second surface 10B side of the basematerial layer 10 and in which an adhesive force is decreased by anexternal stimulus, measuring the integrated tacking force value(F_(2.5)) and the integrated tacking force value (F₃₀) of the adhesiveresin layer (B) measured by method 1 is effective as a design guidelinefor an adhesive film for suppressing position shifting of electroniccomponents in a sealing step.

That is, in the adhesive film 50 according to the present embodiment,setting the integrated tacking force value (F_(2.5)) and the integratedtacking force value (F₃₀) of the adhesive resin layer (B) to each be theabove lower limit value or more makes it possible to suppress theposition shifting of the electronic component in the sealing step.

It is not clear why the use of the adhesive film 50 according to thepresent embodiment makes it possible to suppress position shifting ofelectronic components in the sealing step, but the following reasons maybe considered.

First, studies by the inventors of the present invention found that, inthe step of sealing an electronic component, water and outgas derivedfrom residual volatile components included in the adhesive film,particularly, water and outgas derived from residual volatile componentsincluded in the adhesive resin layer on the side to be attached to thesupport substrate, cause the adhesive film to float and, as a result,causes position shifting of the electronic component. The inventors ofthe present invention carried out further studies based on the abovefindings. As a result, it is clear that, with an adhesive film having anintegrated tacking force value (F_(2.5)) and an integrated tacking forcevalue (F₃₀) of the adhesive resin layer (B), which are measured bymethod 1 and which are the above lower limit value or more,respectively, in the step of sealing the electronic component, floatingdoes not easily occur due to the water or outgas derived from theresidual volatile components included in the adhesive film, inparticular, water or outgas derived from the residual volatilecomponents included in the adhesive resin layer on the side to beattached to the support substrate and, as a result, position shifting ofthe electronic components does not easily occur. That is, it isconsidered that, in an adhesive film in which the integrated tackingforce value (F_(2.5)) and the integrated tacking force value (F₃₀) ofthe adhesive resin layer (B) are the above lower limit values or more,respectively, in the sealing step, there is unlikely to be an adverseinfluence due to water or outgas derived from the residual volatilecomponents, and as a result, it is possible to suppress positionshifting of the electronic components in the sealing step.

In the adhesive film 50 according to the present embodiment, the lowerlimit of the integrated tacking force value (F_(2.5)) is 1.0 gf/sec ormore, but, from the viewpoint that it is possible to further suppressposition shifting of the electronic component in the sealing step, 1.5gf/sec or more is preferable, 2.0 gf/sec or more is more preferable, and2.5 gf/sec or more is even more preferable.

In addition, in the adhesive film 50 according to the presentembodiment, from the viewpoint of effectively suppressing adhesiveresidue on the support substrate side when peeling the support substratefrom the adhesive resin layer (B) and obtaining good detachability fromthe support substrate, the upper limit of the integrated tacking forcevalue (F_(2.5)) is preferably 50.0 gf/sec or less, more preferably 35.0gf/sec or less, even more preferably 25.0 gf/sec or less, still morepreferably 15 gf/sec or less, and particularly preferably 7.5 gf/sec orless.

In addition, in the adhesive film 50 according to the presentembodiment, the lower limit of the integrated tacking force value (F₃₀)is 7.0 gf/sec or more, but, from the viewpoint of being able to furthersuppress the position shifting of the electronic component in thesealing step, 8.0 gf/sec or more is preferable, 9.0 gf/sec or more ismore preferable, and 10.0 gf/sec or more is even more preferable.

In addition, in the adhesive film 50 according to the presentembodiment, from the viewpoint of effectively suppressing adhesiveresidue on the support substrate side when peeling the support substratefrom the adhesive resin layer (B) and obtaining good detachability fromthe support substrate, the upper limit of the integrated tacking forcevalue (F₃₀) is preferably 150.0 gf/sec or less, more preferably 100.0gf/sec or less, even more preferably 80.0 gf/sec or less, still morepreferably 50.0 gf/sec or less, and particularly preferably 25.0 gf/secor less.

In the adhesive film 50 according to the present embodiment, it ispossible to control the integrated tacking force value (F_(2.5)) and theintegrated tacking force value (F₃₀), for example, by controlling thetype and blending ratio of each component forming the adhesive resinlayer (B) and the type and content ratio of each monomer in the adhesiveresin forming the adhesive resin layer (B). More specifically, it ispresumed that the hardness of the adhesive resin layer (B) and thevolatile components included in the adhesive resin layer (B) have aninfluence and there is a tendency for the amount of a cross-linkingagent (B2) and the amount of water and residual solvent included in theadhesive film 50 (particularly the adhesive resin layer (B)) to have aninfluence. Accordingly, it is possible to control the integrated tackingforce value (F_(2.5)) and the integrated tacking force value (F₃₀) inthe above range by controlling the amount and number of functionalgroups of the cross-linking agent (B2), the water included in theadhesive film 50 (particularly the adhesive resin layer (B)), the amountof residual volatile components such as residual solvent, and the like,which will be described below.

From the viewpoint of the balance between mechanical properties andhandleability, the total thickness of the adhesive film 50 according tothe present embodiment is preferably 10 μm or more and 1000 μm or less,and more preferably 20 μm or more and 500 μm or less.

It is possible to use the adhesive film 50 according to the presentembodiment, for example, in a film or the like for temporarily fixingelectronic components in an electronic device manufacturing step, andparticularly, suitable use is possible as a film for temporarily fixingelectronic components in a manufacturing step for a fan-out type WLP.

Next, a description will be given of each layer forming the adhesivefilm 50 according to the present embodiment.

<Base Material Layer>

The base material layer 10 is a layer provided for the purpose ofimproving properties such as the handleability, mechanical properties,and heat resistance of the adhesive film 50.

The base material layer 10 is not particularly limited and examplesthereof include a resin film.

It is possible to use a known thermoplastic resin as the resin formingthe resin film. Examples thereof include one type or two or more typesselected from polyolefins such as polyethylene, polypropylene,poly(4-methyl-1-pentene), and poly(1-butene); polyesters such aspolyethylene terephthalate, polybutylene terephthalate, and polyethylenenaphthalate; polyamides such as nylon-6, nylon-66, and polymethaxyleneadipamide; polyacrylates;

polymethacrylates; polyvinyl chloride; polyvinylidene chloride;polyimides; polyetherimides; ethylene/vinyl acetate copolymers;polyacrylonitrile; polycarbonates; polystyrenes; ionomers; polysulfones;polyethersulfones; polyphenylene ether, and the like.

Among the above, from the viewpoint of excellent balance oftransparency, mechanical strength, price, and the like, one type or twoor more types selected from polypropylene, polyethylene terephthalate,polyethylene naphthalate, polyamide, and polyimide are preferable, andat least one type selected from polyethylene terephthalate andpolyethylene naphthalate is more preferable.

The base material layer 10 may be a single layer or two or more types oflayers.

In addition, the form of the resin film used to form the base materiallayer 10 may be a stretched film, or may be a uniaxially or biaxiallystretched film; however, from the viewpoint of improving the mechanicalstrength of the base material layer 10, the film is preferably auniaxially or biaxially stretched film.

From the viewpoint of obtaining good film properties, the thickness ofthe base material layer 10 is preferably 1 μm or more and 500 μm orless, more preferably 5 μm or more and 300 μm or less, and even morepreferably 10 μm or more and 250 μm or less.

The base material layer 10 may be surface-treated in order to improvethe adhesion with other layers. Specifically, a corona treatment, aplasma treatment, an undercoat treatment, a primer coat treatment, orthe like may be performed.

<Adhesive Resin Layer (A)>

The adhesive resin layer (A) is a layer provided on one surface side ofthe base material layer 10, and, for example, is a layer for contactingthe surface of the electronic component to temporarily fix theelectronic component when the electronic component is sealed with asealing material in the electronic device manufacturing step.

The adhesive resin layer (A) includes an adhesive resin (A1).

Examples of the adhesive resin (A1) include (meth)acrylic adhesive resin(a), a silicone-based adhesive resin, a urethane-based adhesive resin,an olefin-based adhesive resin, a styrene-based adhesive resin, and thelike.

Among the above, the (meth)acrylic adhesive resin (a) is preferable fromthe viewpoint of facilitating the adjustment of the adhesive force andthe like.

As the adhesive resin layer (A), it is also possible to use aradiation-cross-linking adhesive resin layer in which the adhesive forceis decreased by radiation. The radiation cross-linking adhesive resinlayer is cross-linked by the irradiation of radiation and the adhesiveforce is significantly reduced, thus, the adhesive film 50 is easilypeeled from the electronic component. Examples of the radiation includeultraviolet rays, electron beams, infrared rays, and the like.

As the radiation cross-linking adhesive resin layer, an ultravioletcross-linking adhesive resin layer is preferable.

Examples of the (meth)acrylic adhesive resin (a) used in the adhesiveresin layer (A) include a copolymer including a (meth) acrylic acidalkyl ester monomer unit (a1) and a monomer unit (a2) having afunctional group capable of reacting with a cross-linking agent.

In the present embodiment, the (meth)acrylic acid alkyl ester means anacrylic acid alkyl ester, a methacrylic acid alkyl ester, or a mixturethereof.

It is possible to obtain the (meth)acrylic adhesive resin (a) accordingto the present embodiment, for example, by copolymerizing a monomermixture including the (meth)acrylic acid alkyl ester monomer (a1) andthe monomer (a2) having a functional group capable of reacting with across-linking agent.

Examples of the monomer (a1) forming the (meth)acrylic acid alkyl estermonomer unit (a1) include a (meth) acrylic acid alkyl ester having analkyl group having approximately 1 to 12 carbon atoms. A (meth)acrylicacid alkyl ester having an alkyl group having 1 to 8 carbon atoms ispreferable. Specific examples thereof include methyl acrylate, methylmethacrylate, ethyl acrylate, ethyl methacrylate, butyl acrylate, butylmethacrylate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, and thelike. These may be used alone or in a combination of two or more types.

In the (meth) acrylic adhesive resin (a) according to the presentembodiment, when the total of all the monomer units in the (meth)acrylic adhesive resin (a) is 100% by mass, the content of the(meth)acrylic acid alkyl ester monomer unit (a1) is preferably 10% bymass or more and 98.9% by mass or less, more preferably 50% by mass ormore and 97% by mass or less, and even more preferably 85% by mass ormore and 95% by mass or less.

Examples of the monomer (a2) forming the monomer (a2) having afunctional group capable of reacting with the cross-linking agentinclude acrylic acid, methacrylic acid, itaconic acid, mesaconic acid,citraconic acid, fumaric acid, maleic acid, itaconic acid monoalkylester, mesaconic acid monoalkyl ester, citraconic acid monoalkyl ester,fumaric acid monoalkyl ester, maleic acid monoalkyl ester, glycidylacrylate, glycidyl methacrylate, 2-hydroxyethyl acrylate, 2-hydroxyethylmethacrylate, acrylamide, methacrylamide, tert-butylaminoethyl acrylate,tert-butylaminoethyl methacrylate, and the like. Preferable are acrylicacid, methacrylic acid, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, acrylamide, methacrylamide, and the like. These may be usedalone or in a combination of two or more types.

In the (meth) acrylic adhesive resin (a) according to the presentembodiment, when the total of all the monomer units in the (meth)acrylic adhesive resin (a) is 100% by mass, the content of the monomerunit (a2) is preferably 1% by mass or more and 40% by mass or less, morepreferably 1% by mass or more and 20% by mass or less, and even morepreferably 1% by mass or more and 10% by mass or less.

The (meth)acrylic adhesive resin (a) according to the present embodimentmay, in addition to the monomer unit (a1) and the monomer unit (a2),further include a bifunctional monomer unit (a3) and a specificcomonomer (referred to below as a polymerizable surfactant) unit havingproperties as a surfactant.

The polymerizable surfactant has a property of copolymerizing with themonomer (a1), the monomer (a2), and the monomer (a3), and also has anaction as an emulsifier in the case of emulsion polymerization.

Examples of the monomer (a3) forming the bifunctional monomer unit (a3)include allyl methacrylate, allyl acrylate, divinylbenzene, vinylmethacrylate, vinyl acrylate, trimethylolpropane tri (meth) acrylate,pentaerythritol tri (meth) acrylate, dipentaerythritol hexa (meth)acrylate, tetraethylene glycol di (meth) acrylate, or, for example,monomers in which a main chain structure is a propylene glycol type withdiacrylate or dimethacrylate at both ends (for example, manufactured byNOF Corp., trade name: PDP-200, PDP-400, ADP-200, and ADP-400),tetramethylene glycol type monomers (for example, manufactured by NOFCorp.; trade name: ADT-250, ADT-850), mixtures thereof (for example,manufactured by NOF Corp., trade name: ADET-1800 and ADPT-4000), and thelike.

In the (meth) acrylic adhesive resin (a) according to the presentembodiment, when the total of all the monomer units in the (meth)acrylic adhesive resin (a) is 100% by mass, the content of the monomerunit (a3) is preferably 0.1% by mass or more and 30% by mass or less,more preferably 0.1% by mass or more and 15% by mass or less, even morepreferably 0.1% by mass or more and 20% by mass or less, andparticularly preferably 0.1% by mass or more and 5% by mass or less.

Examples of the polymerizable surfactant include a surfactant in which apolymerizable 1-propenyl group is introduced into a benzene ring ofpolyoxyethylene nonylphenyl ether (manufactured by DKS Co., Ltd.; tradename: Aqualon RN-10, RN-20, RN-30, RN-50, and the like), a surfactant inwhich a polymerizable 1-propenyl group is introduced into a benzene ringof ammonium salt of sulfuric acid ester of polyoxyethylene nonylphenylether (manufactured by DKS Co., Ltd.; trade name: Aqualon HS-10, HS-20,HS-1025, and the like), and a sulfosuccinate diester-based surfactanthaving a polymerizable double bond in the molecule (manufactured by KaoCorp.; trade name: Latemul S-120A, S-180A, and the like), or the like.

In the (meth) acrylic adhesive resin (a) according to the presentembodiment, when the total of all the monomer units in the (meth)acrylic adhesive resin (a) is 100% by mass, the content of thepolymerizable surfactant is preferably 0.1% by mass or more and 30% bymass or less, more preferably 0.1% by mass or more and 15% by mass orless, even more preferably 0.1% by mass or more and 20% by mass or less,and particularly preferably 0.1% by mass or more and 5% by mass or less.

The (meth)acrylic adhesive resin (a) according to the present embodimentmay further include a monomer unit formed of a monomer having apolymerizable double bond such as vinyl acetate, acrylonitrile, orstyrene, as necessary.

Examples of the polymerization reaction mechanism of the (meth)acrylicadhesive resin (a) according to the present embodiment include radicalpolymerization, anionic polymerization, cationic polymerization, and thelike. In consideration of the manufacturing cost of the (meth)acrylicadhesive resin (a), the influence of the functional group of themonomer, the influence of ions on the surface of the electroniccomponent, and the like, it is preferable to carry out thepolymerization by radical polymerization.

When polymerizing by a radical polymerization reaction, examples ofradical polymerization initiators include organic peroxides such asbenzoyl peroxide, di-t-butyl peroxide, dicumyl peroxide,3,3,5-trimethylhexanoyl peroxide, di-2-ethylhexylperoxy dicarbonate,methyl ethyl ketone peroxide, t-butylperoxyphthalate,t-butylperoxybenzoate, di-t-butylperoxyacetate,t-butylperoxyisobutyrate, t-butylperoxy-2-hexanoate,t-butylperoxy-2-ethylhexanoate, t-butylperoxy-3,5,5-trimethylhexanoate,acetyl peroxide, isobutyryl peroxide, octanoyl peroxide, t-butylperoxide, and di-t-amyl peroxide; inorganic peroxides such as ammoniumpersulfate, potassium persulfate, and sodium persulfate; azo compoundssuch as 2,2′-azobisisobutyronitrile, 2,2′-azobis-2-methylbutyronitrile,and 4,4′-azobis-4-cyanovaleric acid.

In a case of polymerizing by an emulsion polymerization method, amongthese radical polymerization initiators, inorganic peroxides such aswater-soluble ammonium persulfate, potassium persulfate, and sodiumpersulfate, and azo compounds having a carboxyl group in the moleculesuch as water-soluble 4,4′-azobis-4-cyanovaleric acid are preferable.Considering the influence of ions on the surface of the electroniccomponents, ammonium persulfate and azo compounds having a carboxylgroup in the molecule such as 4,4′-azobis-4-cyanovaleric acid are morepreferable, and azo compounds having a carboxyl group in the moleculesuch as 4,4′-azobis-4-cyanovaleric acid are particularly preferable.

The adhesive resin layer (A) according to the present embodimentpreferably further includes a cross-linking agent (A2) having two ormore cross-linkable functional groups in one molecule, in addition tothe adhesive resin (A1).

A cross-linking agent (A2) having two or more cross-linkable functionalgroups in one molecule is used to react with the functional group of theadhesive resin (A1) and adjust the adhesive force and aggregating force.

Examples of such a cross-linking agent (A2) include epoxy-basedcompounds such as sorbitol polyglycidyl ether, polyglycerol polyglycidylether, pentaerythritol polyglycidyl ether, diglycerol polyglycidylether, glycerol polyglycidyl ether, neopentyl glycol diglycidyl ether,and resorcin diglycidyl ether; isocyanate-based compounds such astetramethylene diisocyanate, hexamethylene diisocyanate, toluenediisocyanate 3 adducts of trimethylolpropane, polyisocyanate,diphenylmethane diisocyanate, and tolylene diisocyanate; aziridine-basedcompounds such as trimethylolpropane-tri-β-aziridinylpropionate,tetramethylolmethane-tri-β-aziridinylpropionate,N,N′-diphenylmethane-4,4′-bis(1-aziridinecarboxamide),N,N′-hexamethylene-1,6-bis(1-aziridinecarboxamide),N,N′-toluene-2,4-bis(1-aziridinecarboxamide), andtrimethylolpropane-tri-β-(2-methylaziridine) propionate; tetrafunctionalepoxy-based compounds such as N,N,N′,N′-tetraglycidyl-m-xylenediamineand 1,3-bis(N,N′-diglycidylaminomethyl) cyclohexane; and melamine-basedcompounds such as hexamethoxymethylolmelamine. These may be used aloneor in a combination of two or more types.

Among the above, it is preferable to include one type or two or moretypes selected from an epoxy-based compound, an isocyanate-basedcompound, and an aziridine-based compound.

The content of the cross-linking agent (A2) is usually preferably in arange in which the number of functional groups in the cross-linkingagent (A2) does not exceed the number of functional groups in theadhesive resin (A1). However, in a case where a functional group isnewly generated in the cross-linking reaction, a case where thecross-linking reaction is slow, or the like, the content thereof may begreater as necessary.

From the viewpoint of improving the balance between the heat resistanceand the adhesive force of the adhesive resin layer (A), the content ofthe cross-linking agent (A2) in the adhesive resin layer (A) ispreferably 0.1 parts by mass or more and 15 parts by mass or less withrespect to 100 parts by mass of the adhesive resin (A1).

When the entire adhesive resin layer (A) is 100% by mass, the totalcontent of the adhesive resin (A1) and the cross-linking agent (A2) inthe adhesive resin layer (A) is preferably 50% by mass or more and 100%by mass or less, more preferably 70% by mass or more and 100% by mass orless, even more preferably 90% by mass or more and 100% by mass or less,and particularly preferably 95% by mass or more and 100% by mass orless. Due to this, it is possible to further suppress adhesive residueon the electronic component side when the adhesive film is peeled offfrom the electronic component.

The thickness of the adhesive resin layer (A) is not particularlylimited, but is, for example, preferably 1 μm or more and 100 μm orless, and more preferably 3 μm or more and 50 μm or less.

It is possible to form the adhesive resin layer (A), for example, bycoating an adhesive on the base material layer 10. The adhesive may bedissolved in a solvent and coated as a coating solution, coated as anaqueous emulsion, or directly coated as a liquid adhesive.

Among the above, an aqueous emulsion coating solution is preferable.Examples of the aqueous emulsion coating solution include coatingsolutions in which the (meth)acrylic adhesive resin (a), asilicone-based adhesive resin, a urethane-based adhesive resin, anolefin-based adhesive resin, a styrene-based adhesive resin, or the likeis dispersed in water.

An adhesive coating solution dissolved in an organic solvent may beused. The organic solvent is not particularly limited and may beappropriately selected from known organic solvents in consideration ofsolubility and drying time. Examples of organic solvents includeester-based organic solvents such as ethyl acetate and methyl acetate;ketone-based organic solvents such as acetone and MEK; aromatic-basedorganic solvents such as benzene, toluene, and ethylbenzene; linear orcyclic aliphatic-based organic solvents such as heptane, hexane, andcyclohexane; alcohol-based organic solvents such as isopropanol andbutanol. Ethyl acetate and toluene are preferable as the organicsolvent. These solvents may be used alone as one type or used in amixture of two or more types.

As a method for coating the adhesive coating solution, it is possible toadopt a coating method known in the related art, for example, a rollcoater method, a reverse roll coater method, a gravure roll method, abar coating method, a comma coater method, a die coater method, or thelike. The drying conditions of the coated adhesive are not particularlylimited, but, generally, drying for 10 seconds to 10 minutes in atemperature range of 80 to 200° C. is preferable. More preferably,drying is performed at 80 to 170° C. for 15 seconds to 5 minutes. Inorder to sufficiently accelerate the cross-linking reaction between thecross-linking agent and the adhesive, the adhesive coating solution maybe heated at 40 to 80° C. for approximately 5 to 300 hours after drying.

In addition, the base material layer 10 and the adhesive resin layer (A)may be formed by coextrusion molding, or the film-shaped base materiallayer 10 and the film-shaped adhesive resin layer (A) may be formed bylaminating (laminated).

<Adhesive Resin Layer (B)>

The adhesive film 50 according to the present embodiment is providedwith an adhesive resin layer (B) on the second surface 10B side of thebase material layer 10 on the opposite side to the first surface 10A,the adhesive force of which is decreased by an external stimulus.

Due to this, it is possible to easily peel the adhesive film 50 from thesupport substrate 80 by applying an external stimulus.

Here, examples of the adhesive resin layer (B), the adhesive force ofwhich is decreased by an external stimulus, include a heat-peelableadhesive resin layer, the adhesive force of which is decreased byheating, and a radiation-peelable adhesive resin layer, the adhesiveforce of which is decreased by radiation, and the like. Among the above,a heat-peelable adhesive resin layer, the adhesive force of which isdecreased by heating, is preferable.

Examples of the heat-peelable adhesive resin layer include adhesiveresin layers formed of a heat-expandable adhesive including a gasgenerating component, a heat-expandable adhesive includingheat-expandable microspheres capable of expanding to decrease theadhesive force, a heat-expandable adhesive, the adhesive force of whichis decreased by the cross-linking reaction of the adhesive componentsdue to heat, or the like.

In the present embodiment, the heat-expandable adhesive used in theadhesive resin layer (B) is an adhesive, the adhesive force of which isdecreased or lost by heating at a temperature over 150° C., for example.For example, it is possible to select a material which does not peel ata temperature of 150° C. or lower and which does peel at a temperatureover 150° C. and the heat-expandable adhesive preferably has an adhesiveforce such that the adhesive film 50 does not peel from the supportsubstrate 80 during the electronic device manufacturing step.

Here, it is possible to evaluate whether the adhesive force is decreasedor lost by heating at a temperature over 150° C., for example, byattaching the adhesive resin layer (B) side to a stainless steel plate,performing a heat treatment at 140° C. for 1 hour, then heating for 2minutes at a temperature over 150° C. and measuring the peel force fromthe stainless steel plate. The specific heating temperature when heatingat a temperature over 150° C. is set to a temperature higher than thetemperature at which the gas is generated or the temperature at whichthe heat-expandable microspheres are heat-expanded and is appropriatelyset depending on the gas to be generated or the type of heat-expandablemicrospheres. In the present embodiment, the loss of adhesive forcemeans, for example, a case where the 180° peel force measured under theconditions of 23° C. and a tensile speed of 300 mm/min becomes less than0.5 N/25 mm.

As the gas generating component used in the heat-expandable adhesive,for example, it is possible to use an azo compound, an azide compound, aMeldrum's acid derivative, or the like. In addition, it is also possibleto use inorganic foaming agents such as ammonium carbonate, ammoniumhydrogencarbonate, sodium hydrogencarbonate, ammonium nitrite, sodiumborohydride, and various azides, or water; salts of fluoroalkane-basedcompounds such as trichloromonofluoromethane anddichloromonofluoromethane; azo-based compounds such asazobisisobutyronitrile, azodicarbonamide, and barium azodicarboxylate;hydrazine-based compounds such as paratoluenesulfonyl hydrazide,diphenylsulfone-3,3′-disulfonylhydrazide, 4,4′-oxybis (benzenesulfonylhydrazide) and allylbis (sulfonylhydrazide); semicarbazide-basedcompounds such as p-toluylenesulfonyl semicarbazide, and 4,4′-oxybis(benzenesulfonyl semicarbazide); triazole-based compounds such as5-morpholyl-1,2,3,4-thiatriazole; organic foaming agents such asN-nitroso compounds such as N,N′-dinitrosopentamethylenetetramine, andN,N′-dimethyl-N,N′-dinitrosoterephthalamide, and the like. The gasgenerating component may be added to the adhesive resin (B1) or may bedirectly bonded to the adhesive resin (B1).

As the heat-expandable microspheres used for the heat-expandableadhesive, for example, it is possible to use a microencapsulated foamingagent. Examples of such heat-expandable microspheres includemicrospheres in which a substance that is easily gasified and expandedby heating such as isobutane, propane, and pentane is sealed in a shellhaving elasticity, or the like. Examples of the material forming theshell include vinylidene chloride-acrylonitrile copolymer, polyvinylalcohol, polyvinyl butyral, polymethyl methacrylate, polyacrylonitrile,polyvinylidene chloride, polysulfone, and the like. It is possible tomanufacture heat-expandable microspheres by, for example, a coacervationmethod, an interfacial polymerization method, or the like.

It is possible to add heat-expandable microspheres to the adhesiveresin.

It is possible to appropriately set the content of at least one typeselected from the gas generating component and the heat-expandablemicrospheres according to the expansion ratio and the decrease inadhesive force of the heat-peelable adhesive resin layer (B) and thelike without being particularly limited; however, for example, withrespect to 100 parts by mass of the adhesive resin (B1) in theheat-peelable adhesive resin layer (B), the content is, for instance, 1part by mass or more and 150 parts by mass or less, preferably 10 partsby mass or more and 130 parts by mass or less, and more preferably 12parts by mass or more and 100 parts by mass or less.

It is preferable to implement the design such that the temperature atwhich gas is generated or the temperature at which the heat-expandablemicrospheres heat-expand is over 150° C.

Examples of the adhesive resin (B1) forming the heat-expandable adhesiveinclude (meth)acrylic resin (b), urethane-based resin, silicone-basedresin, polyolefin-based resin, polyester-based resin, polyamide-basedresin, fluorine resin-based resins, styrene-diene block copolymer-basedresins, and the like. Among these, the (meth)acrylic resin (b) ispreferable.

Examples of the (meth)acrylic adhesive resin (b) used in the adhesiveresin layer (B) include a copolymer including the (meth) acrylic acidalkyl ester monomer unit (b1) and the monomer unit (b2) having afunctional group capable of reacting with a cross-linking agent.

In the present embodiment, (meth) acrylic acid alkyl ester means acrylicacid alkyl ester, methacrylic acid alkyl ester, or a mixture thereof.

It is possible to obtain the (meth)acrylic adhesive resin (b) accordingto the present embodiment, for example, by copolymerizing a monomermixture including a (meth) acrylic acid alkyl ester monomer (b1) and amonomer (b2) having a functional group capable of reacting with across-linking agent.

Examples of the monomer (b1) forming the (meth)acrylic acid alkyl estermonomer unit (b1) include a (meth) acrylic acid alkyl ester having analkyl group having approximately 1 to 12 carbon atoms. A (meth)acrylicacid alkyl ester having an alkyl group having 1 to 8 carbon atoms ispreferable. Specific examples thereof include methyl acrylate, methylmethacrylate, ethyl acrylate, ethyl methacrylate, butyl acrylate, butylmethacrylate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, and thelike. These may be used alone or in a combination of two or more types.

In the (meth) acrylic adhesive resin (b) according to the presentembodiment, when the total of all the monomer units in the (meth)acrylic adhesive resin (b) is 100% by mass, the content of the(meth)acrylic acid alkyl ester monomer unit (b1) is preferably 10% bymass or more and 98.9% by mass or less, more preferably 50% by mass ormore and 97% by mass or less, and even more preferably 85% by mass ormore and 95% by mass or less.

Examples of the monomer (b2) forming the monomer (b2) having afunctional group capable of reacting with the cross-linking agentinclude acrylic acid, methacrylic acid, itaconic acid, mesaconic acid,citraconic acid, fumaric acid, maleic acid, itaconic acid monoalkylester, mesaconic acid monoalkyl ester, citraconic acid monoalkyl ester,fumaric acid monoalkyl ester, maleic acid monoalkyl ester, glycidylacrylate, glycidyl methacrylate, 2-hydroxyethyl acrylate, 2-hydroxyethylmethacrylic acid, acrylamide, methacrylamide, tert-butylaminoethylacrylate, tert-butylaminoethyl methacrylate, and the like. Preferableexamples are acrylic acid, methacrylic acid, 2-hydroxyethyl acrylate,2-hydroxyethyl methacrylic acid, acrylamide, methacrylamide, and thelike. These may be used alone or in a combination of two or more types.

In the (meth) acrylic adhesive resin (b) according to the presentembodiment, when the total of all the monomer units in the (meth)acrylic adhesive resin (b) is 100% by mass, the content of the monomerunit (b2) is preferably 1% by mass or more and 40% by mass or less, morepreferably 1% by mass or more and 20% by mass or less, and even morepreferably 1% by mass or more and 10% by mass or less.

The (meth)acrylic adhesive resin (b) according to the present embodimentmay further include a bifunctional monomer unit (b3) and a specificcomonomer (referred to below as a polymerizable surfactant) unit havinga property as a surfactant in addition to the monomer unit (b1) or themonomer unit (b2).

The polymerizable surfactant has a property of copolymerizing with themonomer (b1), the monomer (b2), and the monomer (b3), and has an actionas an emulsifier in a case of emulsion polymerization.

Examples of the monomer (b3) forming the bifunctional monomer unit (b3)include allyl methacrylate, allyl acrylate, divinylbenzene, vinylmethacrylate, vinyl acrylate, trimethylolpropane tri(meth)acrylate,pentaerythritol tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate,tetraethylene glycol di (meth) acrylate, or, for example, monomers inwhich a main chain structure is a propylene glycol type with diacrylateor dimethacrylate at both ends (for example, manufactured by NOF Corp.,trade name: PDP-200, PDP-400, ADP-200, and ADP-400), tetramethyleneglycol type monomers (for example, manufactured by NOF Corp.; tradename: ADT-250, ADT-850), mixtures thereof (for example, manufactured byNOF Corp., trade name: ADET-1800 and ADPT-4000), and the like.

In the (meth) acrylic adhesive resin (b) according to the presentembodiment, when the total of all the monomer units in the (meth)acrylic adhesive resin (b) is 100% by mass, the content of the monomerunit (b3) is preferably 0.1% by mass or more and 30% by mass or less,more preferably 0.1% by mass or more and 15% by mass or less, even morepreferably 0.1% by mass or more and 20% by mass or less, andparticularly preferably 0.1% by mass or more and 5% by mass or less.

Examples of the polymerizable surfactant include a surfactant in which apolymerizable 1-propenyl group is introduced into a benzene ring ofpolyoxyethylene nonylphenyl ether (manufactured by DKS Co., Ltd.; tradename: Aqualon RN-10, RN-20, RN-30, RN-50, and the like), a surfactant inwhich a polymerizable 1-propenyl group is introduced into a benzene ringof ammonium salt of sulfuric acid ester of polyoxyethylene nonylphenylether (manufactured by DKS Co., Ltd.; trade name: Aqualon HS-10, HS-20,HS-1025, and the like), and a sulfosuccinate diester-based surfactanthaving a polymerizable double bond in the molecule (manufactured by KaoCorp.; trade name: Latemul S-120A, S-180A, and the like), or the like.

In the (meth) acrylic adhesive resin (b) according to the presentembodiment, when the total of all the monomer units in the (meth)acrylic adhesive resin (b) is 100% by mass, the content of thepolymerizable surfactant is preferably 0.1% by mass or more and 30% bymass or less, more preferably 0.1% by mass or more and 15% by mass orless, even more preferably 0.1% by mass or more and 20% by mass or less,and particularly preferably 0.1% by mass or more and 5% by mass or less.

The (meth)acrylic adhesive resin (b) according to the present embodimentmay further contain, as necessary, a monomer unit formed of a monomerhaving a polymerizable double bond such as vinyl acetate, acrylonitrile,or styrene.

Examples of the polymerization reaction mechanism of the (meth)acrylicadhesive resin (b) according to the present embodiment include radicalpolymerization, anionic polymerization, cationic polymerization, and thelike. In consideration of the manufacturing cost of the (meth)acrylicadhesive resin (b), the influence of the functional group of themonomer, the influence of ions on the surface of the electroniccomponent, and the like, it is preferable to carry out thepolymerization by radical polymerization.

When polymerizing by a radical polymerization reaction, examples ofradical polymerization initiators include organic peroxides such asbenzoyl peroxide, di-t-butyl peroxide, dicumyl peroxide,3,3,5-trimethylhexanoyl peroxide, di-2-ethylhexylperoxy dicarbonate,methyl ethyl ketone peroxide, t-butylperoxyphthalate,t-butylperoxybenzoate, di-t-butylperoxyacetate,t-butylperoxyisobutyrate, t-butylperoxy-2-hexanoate,t-butylperoxy-2-ethylhexanoate, t-butylperoxy-3,5,5-trimethylhexanoate,acetyl peroxide, isobutyryl peroxide, octanoyl peroxide, t-butylperoxide, and di-t-amyl peroxide; inorganic peroxides such as ammoniumpersulfate, potassium persulfate, and sodium persulfate; and azocompounds such as 2,2′-azobisisobutyronitrile,2,2′-azobis-2-methylbutyronitrile, and 4,4′-azobis-4-cyanovaleric acid.

In a case of polymerizing by an emulsion polymerization method, amongthese radical polymerization initiators, inorganic peroxides such aswater-soluble ammonium persulfate, potassium persulfate, and sodiumpersulfate, and, similarly, azo compounds having a carboxyl group in themolecule such as water-soluble 4,4′-azobis-4-cyanovaleric acid arepreferable. Considering the influence of ions on the surface of theelectronic components, ammonium persulfate and azo compounds having acarboxyl group in the molecule such as 4,4′-azobis-4-cyanovaleric acidare more preferable, and azo compounds having a carboxyl group in themolecule such as 4,4′-azobis-4-cyanovaleric acid are particularlypreferable.

From the viewpoint of more stable peeling from the support substrate,the adhesive resin layer (B) according to the present embodimentpreferably further includes a cross-linking agent (B2) having two ormore cross-linkable functional groups in a molecule in addition to theadhesive resin (B1).

A cross-linking agent (B2) having two or more cross-linkable functionalgroups in one molecule is used to adjust the adhesive force andaggregating force by reacting with the functional group of the adhesiveresin (B1).

Examples of the cross-linking agent (B2) include epoxy-based compoundssuch as sorbitol polyglycidyl ether, polyglycerol polyglycidyl ether,pentaerythritol polyglycidyl ether, diglycerol polyglycidyl ether,glycerol polyglycidyl ether, neopentyl glycol diglycidyl ether, andresorcin diglycidyl ether; isocyanate-based compounds such astetramethylene diisocyanate, hexamethylene diisocyanate, toluenediisocyanate 3 adducts of trimethylolpropane, polyisocyanate,diphenylmethane diisocyanate, and tolylene diisocyanate; aziridine-basedcompounds such as trimethylolpropane-tri-β-aziridinylpropionate,tetramethylolmethane-tri-β-aziridinylpropionate,N,N′-diphenylmethane-4,4′-bis(1-aziridinecarboxamide),N,N′-hexamethylene-1,6-bis(1-aziridinecarboxamide),N,N′-toluene-2,4-bis(1-aziridinecarboxamide), andtrimethylolpropane-tri-β-(2-methylaziridine) propionate; tetrafunctionalepoxy-based compounds such as N,N,N′,N′-tetraglycidyl-m-xylenediamineand 1,3-bis(N,N′-diglycidylaminomethyl) cyclohexane; and melamine-basedcompounds such as hexamethoxymethylolmelamine, and the like. These maybe used alone or in a combination of two or more types.

Among the above, it is preferable to include one type or two or moretypes selected from epoxy-based compounds, isocyanate-based compounds,and aziridine-based compounds.

The content of the cross-linking agent (B2) is usually preferably in anapproximate range in which the number of functional groups in thecross-linking agent (B2) does not exceed the number of functional groupsin the adhesive resin (B1). However, in a case where a functional groupis newly generated in the cross-linking reaction, a case where thecross-linking reaction is slow, or the like, the content thereof may begreater as necessary.

From the viewpoint of more stable peeling from the support substrate,the content of the cross-linking agent (B2) in the adhesive resin layer(B) is preferably 0.5 parts by mass or more and 4.0 parts by mass orless with respect to 100 parts by mass of the adhesive resin (B1), andmore preferably 1.0 part by mass or more and 3.0 parts by mass or less.

When the entire adhesive resin layer (B) is 100% by mass, the totalcontent of the adhesive resin (B1) and the cross-linking agent (B2) inthe adhesive resin layer (B) is preferably 50% by mass or more and 100%by mass or less, more preferably 70% by mass or more and 100% by mass orless, even more preferably 90% by mass or more and 100% by mass or less,and particularly preferably 95% by mass or more and 100% by mass orless. Due to this, it is possible to further suppress position shiftingof the electronic component in the sealing step.

When the total of the adhesive resin layer (B) is 100% by mass, thetotal content of at least one type selected from the adhesive resin(B1), the cross-linking agent (B2), and the gas generating component andthe heat-expandable microspheres in the adhesive resin layer (B) ispreferably 50% by mass or more and 100% by mass or less, more preferably70% by mass or more and 100% by mass or less, even more preferably 90%by mass or more and 100% by mass or less, and particularly preferably95% by mass or more and 100% by mass or less.

In addition, from the viewpoint of stably holding the electroniccomponent on the adhesive resin layer (A) when an external stimulus isapplied so as to decrease the adhesive force of the adhesive resin layer(B) and peel the support substrate from the adhesive resin layer (B), inthe adhesive film 50 according to the present embodiment, when the totalof the adhesive resin layer (A) is 100% by mass, the content of at leastone type selected from the gas generating component and theheat-expandable microspheres in the adhesive resin layer (A) ispreferably 0.1% by mass or less, more preferably 0.05% by mass or less,even more preferably 0.01% by mass or less, and particularly preferablysuch that at least one type selected from a gas generating component andheat-expandable microspheres is not included in the adhesive resin layer(A).

From the viewpoint of improving the adhesion to the support substrate,the adhesive resin layer (B) according to the present embodimentpreferably includes a tackifying resin in addition to the adhesive resin(B1). It is preferable for the adhesive resin layer (B) to contain atackifying resin in order to easily adjust the adhesion with the supportsubstrate at around room temperature. The tackifying resin preferablyhas a softening point of 100° C. or higher. Specific examples of thetackifying resin include rosin-based resins such as rosin-basedderivatives subjected to esterification and the like; terpene-basedresins such as α-pinene-based, β-pinene-based, dipentene-based, andterpene-phenol-based resins; natural rosins such as gum-based,wood-based, and tall oil-based rosins; hydrogenated, disproportionated,polymerized, maleated, petroleum resins in these natural rosins;coumarone-indene resins and the like.

Among the above, examples having a softening point in a range of 100 to160° C. are more preferable, and examples having a softening point in arange of 120 to 150° C. are particularly preferable. When the tackifyingresin having a softening point in the range described above is used, notonly is the contamination and adhesive residue on the support substratesmall, but it is possible to further improve the adhesion to the supportsubstrate in a working environment. Further, when a polymerized rosinester-based tackifying resin is used as the tackifying resin, not onlyis contamination and adhesive residue on the support substrate small,but the adhesion with the support substrate in an environment of 80 to130° C. also improves and, after expansion of the heat-expandablemicrospheres, it is possible to more easily carry out the peeling fromthe support substrate.

The blending ratio of the tackifying resin may be appropriately selectedsuch that it is possible to adjust the elastic modulus of the adhesiveresin layer (B) in a desired predetermined numerical range, withoutbeing particularly limited. However, from the viewpoint of the elasticmodulus of the adhesive resin layer (B) and the initial peeling force,the blending ratio is preferably 1 to 100 parts by mass with respect to100 parts by mass of the adhesive resin (B1). When the blending ratio ofthe tackifying resin is the lower limit value described above or morewith respect to 100 parts by mass of the adhesive resin (B1), theadhesion with the support substrate during work tends to be good. On theother hand, when the blending ratio is the upper limit value describedabove or less, the sticking property to the support substrate at roomtemperature tends to be good. From the viewpoint of adhesion to thesupport substrate and sticking property at room temperature, theblending ratio of the tackifying resin is more preferably 2 to 50 partsby mass with respect to 100 parts by mass of the adhesive resin (B1). Inaddition, the acid value of the tackifying resin is preferably 30 orless. If the acid value of the tackifying resin is the upper limit valuedescribed above or less, adhesive residue tends to be less likely tooccur on the support substrate during peeling.

The thickness of the adhesive resin layer (B) is not particularlylimited, but, for example, is preferably 5 μm or more and 300 μm orless, and more preferably 20 μm or more and 150 μm or less.

It is possible to form the adhesive resin layer (B), for example, by amethod for coating an adhesive coating solution on the base materiallayer 10, a method for transferring the adhesive resin layer (B) formedon the separator onto the base material 10, and the like.

As a method for coating the adhesive coating solution, it is possible toadopt a coating method known in the related art, for example, a rollcoater method, a reverse roll coater method, a gravure roll method, abar coating method, a comma coater method, a die coater method, or thelike. The drying conditions of the coated adhesive are not particularlylimited, but, generally, drying for 10 seconds to 10 minutes in atemperature range of 80 to 200° C. is preferable. More preferably,drying is performed at 80 to 170° C. for 15 seconds to 5 minutes. Inorder to sufficiently accelerate the cross-linking reaction between thecross-linking agent and the adhesive, the adhesive coating solution maybe heated at 40 to 80° C. for approximately 5 to 300 hours after drying.

In addition, the base material layer 10 and the adhesive resin layer (B)may be formed by coextrusion molding, or the film-shaped base materiallayer 10 and the film-shaped adhesive resin layer (B) may be formed bylaminating (laminated).

<Other Layers>

The adhesive film 50 according to the present embodiment may be furtherprovided with, for example, an uneven absorption layer, a shockabsorption layer, an easy-adhesion layer, or the like, between the basematerial layer 10 and the adhesive resin layer (A) or between the basematerial layer 10 and the adhesive resin layer (B) as long as the effectof the present embodiment is not impaired.

The uneven absorption layer is preferably formed of a natural rubber, asynthetic rubber, or a synthetic resin having rubber elasticity having aShore D type hardness according to D type Shore of ASTM D-2240 of, forexample, 50 or less, preferably 40 or less. The thickness of the unevenabsorption layer is, for example, 500 μm or less, preferably 5 to 300and more preferably 10 to 150 μm.

Examples of the synthetic rubber and synthetic resin includenitrile-based, diene-based and acrylic-based synthetic rubbers,polyolefin-based and polyester-based thermoplastic elastomers, syntheticresins having elasticity such as ethylene/vinyl acetate copolymers,polyurethane, polybutadiene, and soft polyvinyl chloride. Here, in thepresent embodiment, even with an essentially hard polymer such aspolyvinyl chloride, it is also possible to use an example which hasrubber elasticity in combination with a compounding agent such as aplasticizer or a softener. In addition, it is possible to preferably usethe adhesive resins and the like exemplified in the adhesive resin layer(A) and adhesive resin layer (B) described above for forming the unevenabsorption layer.

2. Electronic Device Manufacturing Method

Next, a description will be given of a method for manufacturing theelectronic device according to the present embodiment. FIGS. 2 and 3 arecross-sectional views schematically showing an example of a method formanufacturing an electronic device of an embodiment according to thepresent invention.

The electronic device manufacturing method according to the presentembodiment is provided with at least the following four steps.

(1) A step of preparing a structure 100 provided with the adhesive film50, an electronic component 70 attached to the adhesive resin layer (A)of the adhesive film 50, and the support substrate 80 attached to anadhesive resin layer (B) of the adhesive film 50

(2) A step of sealing the electronic component 70 with a sealingmaterial 60

(3) A step of peeling the support substrate 80 from the structure 100 bydecreasing the adhesive force of the adhesive resin layer (B) byapplying an external stimulus

(4) A step of peeling the adhesive film 50 from the electronic component70

Then, in the method for manufacturing the electronic device according tothe present embodiment, the adhesive film 50 according to the presentembodiment described above is used as the adhesive film for temporarilyfixing the electronic component 70.

A description will be given below of each step of the method formanufacturing an electronic device according to the present embodiment.

(Step (1))

First, A structure 100 is prepared which is provided with the adhesivefilm 50, the electronic component 70 attached to the adhesive resinlayer (A) of the adhesive film 50, and the support substrate 80 attachedto the adhesive resin layer (B) of the adhesive film 50.

It is possible to manufacture the structure 100, for example, by thefollowing procedure.

First, the adhesive film 50 is attached onto the support substrate 80such that the adhesive resin layer (B) is on the support substrate 80side. A protective film may be attached on the adhesive resin layer (B),and it is possible to peel off the protective film and to attach theexposed surface of the adhesive resin layer (B) to the surface of thesupport substrate 80.

As the support substrate 80, for example, it is possible to use a quartzsubstrate, a glass substrate, a SUS substrate, or the like.

Next, it is possible to obtain the structure 100 by arranging theelectronic component 70 on the adhesive resin layer (A) of the adhesivefilm 50 attached on the support substrate 80.

Examples of the electronic component 70 include a semiconductor chipsuch as an IC, an LSI, a discrete, a light emitting diode, or a lightreceiving element, a semiconductor panel, a semiconductor package, orthe like.

(Step (2))

Next, the electronic component 70 is sealed with the sealing material60.

The electronic component 70 is covered with the sealing material 60, andthe electronic component 70 is sealed by curing the sealing material 60at a temperature of 150° C. or lower, for example.

In addition, the form of the sealing material 60 is not particularlylimited, but is, for example, a granular form, a sheet form, or a liquidform.

The sealing material 60 is not particularly limited, but, for example,it is possible to use an epoxy resin-based sealing material using anepoxy resin.

In particular, a liquid epoxy resin-based sealing material is preferablefrom the viewpoint of improving the affinity of the sealing material 60with the adhesive film 50 and being able to more evenly seal theelectronic component 70.

As such an epoxy resin-based sealing material, for example, it ispossible to use the T693/R4000 series, T693/R1000 series, T693/R5000series, and the like manufactured by Nagase Chemtex Corp.

Examples of the sealing method include transfer molding, injectionmolding, compression molding, cast molding, and the like.

After sealing the electronic component 70 with the sealing material 60,for example, the sealing material 60 is cured by heating at atemperature of 150° C. or less and the structure 100 in which theelectronic component 70 is sealed is obtained.

(Step (3))

Next, the adhesive force of the adhesive resin layer (B) is decreased byapplying an external stimulus and the support substrate 80 is peeledfrom the structure 100.

It is possible to easily remove the support substrate 80 from theadhesive film 50 by, for example, sealing the electronic component 70and then heating at a temperature over 150° C. to decrease the adhesiveforce of the adhesive resin layer (B).

(Step (4))

Next, the adhesive film 50 is removed from the electronic component 70to obtain the electronic device 200.

Examples of a method for removing the adhesive film 50 from theelectronic component 70 include a mechanical peeling method, a methodfor decreasing the adhesive force of the surface of the adhesive film 50and then peeling the adhesive film 50, and the like.

(Step (5))

As shown in FIG. 3 , the method for manufacturing an electronic deviceaccording to the present embodiment may be further provided with a step(5) of forming a wiring layer 310 and a bump 320 on an exposed surfaceof the obtained electronic device 200 to obtain the electronic device300.

The wiring layer 310 is provided with a pad (not shown) which is anexternal connection terminal formed on the outermost surface, and wiring(not shown) which electrically connects the exposed electronic component70 and the pad. It is possible to form the wiring layer 310 by a methodknown in the related art and the structure thereof may be multi-layer.

Then, it is possible to obtain the electronic device 300 by forming thebump 320 on the pad of the wiring layer 310. Examples of the bump 320include a solder bump, a gold bump, and the like. It is possible to formthe solder bump, for example, by arranging a solder ball on a pad whichis an external connection terminal of the wiring layer 310 and carryingout heating to melt (reflow) the solder.

It is possible to form the gold bump by methods such as a ball bondingmethod, a plating method, or an Au ball transfer method.

(Step (6))

The electronic device manufacturing method according to the presentembodiment may be further provided with a step (6) of dicing theelectronic device 300 to obtain a plurality of electronic devices 400,as shown in FIG. 3 .

It is possible to perform the dicing of the electronic device 300 by aknown method.

A description was given above of the embodiments of the presentinvention, but these are Examples of the present invention and it isalso possible to adopt various configurations other than the above.

Here, the present invention is not limited to the embodiments describedabove and modifications, improvements, and the like in a range in whichit is possible to achieve the object of the present invention areincluded in the present invention.

EXAMPLES

A specific description will be given below of the present invention withreference to Examples, but the present invention is not limited thereto.

Details of the materials used to manufacture the adhesive film are asfollows.

<Adhesive Resin Solution SA1>

Into deionized pure water, 0.5 parts by mass of4,4′-azobis-4-cyanovaleric acid (manufactured by Otsuka Chemical Co.,Ltd.; trade name: ACVA) as a polymerization initiator, 78 parts by massof n-butyl acrylate and 10 parts by mass of methyl methacrylate as themonomer (a1), 9 parts by mass of 2-hydroxyethyl methacrylate as themonomer (a2), and 3 parts by mass of a polymerizable surfactant in whicha polymerizable 1-propenyl group was introduced into a benzene ring ofammonium salt of sulfuric acid ester of polyoxyethylene nonylphenylether (manufactured by DKS Co., Ltd.; trade name: Aqualon HS-1025) wereeach added, and emulsion polymerization was carried out for 8 hours at70 to 72° C. while stirring to obtain an acrylic-based resin emulsion.The result was neutralized with aqueous ammonia (pH=7.0) to obtain anadhesive resin solution SA1 having a solid content concentration of42.5%.

<Adhesive Resin Solution SA2>

Into deionized pure water, 0.5 parts by mass of ammonium persulfate as apolymerization initiator, 61 parts by mass of 2-ethylhexyl acrylate, 20parts by mass of acrylic acid-n-butyl, and 9 parts by mass of methylmethacrylate as the monomer (a1), 3 parts by mass of 2-hydroxyethylmethacrylate as the monomer (a2), 1 part by mass of polytetramethyleneglycol diacrylate (manufactured by NOF Corp.; trade name; ADT-250) as amonomer (a3), and 2 parts by mass of a polymerizable surfactant in whicha polymerizable 1-propenyl group was introduced into a benzene ring ofan ammonium salt of a sulfuric acid ester of polyoxyethylene nonylphenylether (manufactured by DKS Co., Ltd.; trade name: Aqualon HS-1025) wereeach added, and emulsion polymerization was carried out for 8 hours at70 to 72° C. while stirring to obtain an acrylic-based resin emulsion.The result was neutralized with aqueous ammonia (pH=7.0) to obtain anadhesive resin solution SA2 having a solid content concentration of56.5%.

<Adhesive Coating Solution A1>

55 parts by mass of adhesive resin solution SA1, 45 parts by mass ofadhesive resin solution SA2, 0.5 parts by mass of dimethylethanolamine,and 4 parts by mass of an epoxy-based compound (Ex-1610, manufactured byNagase Chemtex Corp.) as a cross-linking agent were mixed together toobtain an adhesive coating solution A1.

<Adhesive Resin Solution SB1>

In a mixed solvent including ethyl acetate and toluene, 0.5 parts bymass of t-butylperoxy-2-ethylhexanoate (manufactured by NOF Corp.; tradename: Perbutyl O (registered trademark)) as a polymerization initiator,35 parts by weight of 2-ethylhexyl acrylate, 40 parts by mass of acrylicacid-n-butyl, and 15 parts by mass of ethyl acrylate as monomer (b1), 10parts by mass of 2-hydroxyethyl methacrylate as monomer (b2) were eachadded and solution polymerization was carried out at 83 to 87° C. for 11hours while stirring to obtain an acrylic-based resin solution having asolid content concentration of 45% by mass. The result was set as theadhesive resin solution SB1.

<Adhesive Coating Solution B1>

100 parts by mass of the adhesive resin solution SB1 and 0.9 parts bymass (2 parts by mass with respect to 100 parts by mass of the adhesiveresin) of an isocyanate-based cross-linking agent (manufactured byMitsui Chemicals, Inc.; trade name: Olester P49-75S) were each mixed andthe solid content concentration was adjusted to 40% with ethyl acetateto obtain an adhesive coating solution B1.

<Adhesive Coating Solution B2>

100 parts by mass of the adhesive resin solution SB1, 2.25 parts byweight of a polymerized rosin ester-based tackifier (manufactured byArakawa Chemical Industries, Ltd.; trade name: Pensel D-125) (5 parts bymass with respect to 100 parts by mass of adhesive resin), 1.2 parts bymass of an isocyanate-based cross-linking agent (manufactured by MitsuiChemicals, Inc.; trade name: Olester P49-75S) (2 parts by mass withrespect to 100 parts by mass of adhesive resin), 6.75 parts by mass ofheat-expandable microspheres (Sekisui Chemical Co. , Ltd.; trade name:Advancell EM-503) (15 parts by mass with respect to 100 parts by mass ofthe adhesive resin) were each mixed and the solid content concentrationwas adjusted to 30% with ethyl acetate to prepare an adhesive coatingsolution B2.

<Adhesive Resin Solution SB2>

In a mixed solvent including ethyl acetate and toluene, 0.25 parts bymass of t-butylperoxy-2-ethylhexanoate (manufactured by NOF Corp.; tradename: Perbutyl O (registered trademark)) as a polymerization initiator,72 parts by mass of acrylic acid-n-butyl as the monomer (b1), 18 partsby mass of methyl methacrylate, 7 parts by mass of 2-hydroxyethylmethacrylate as the monomer (b2), and 3 parts by mass of acrylic acidwere each added and solution polymerization was carried out at 83 to 87°C. for 11 hours while stirring to obtain an acrylic-based resin solutionhaving a solid content concentration of 45% by mass. The result was setas the adhesive resin solution SB2.

<Adhesive Coating Solution B3>

100 parts by mass of the adhesive resin solution SB2, 0.05 parts by massof dimethylethanolamine, and 1.35 parts by mass of epoxy-basedcross-linking agent (Ex-614 manufactured by Nagase Chemtex Corp.) (3parts by mass with respect to 100 parts by mass of the adhesive resin)were each mixed and the solid content concentration was adjusted to 40%with ethyl acetate to obtain an adhesive coating solution B3.

<Adhesive Coating Solution B4>

100 parts by mass of the adhesive resin solution SB2, 2.25 parts byweight of a polymerized rosin ester-based tackifier (manufactured byArakawa Chemical Industries, Ltd.; trade name: Pensel D-125) (5 parts bymass with respect to 100 parts by mass of adhesive resin), 1.2 parts bymass of an epoxy-based cross-linking agent (manufactured by NagaseChemtex Corp., Ex-1610) (2 parts by mass with respect to 100 parts bymass of adhesive resin), 9 parts by mass of heat-expandable microspheres(Sekisui Chemical Co., Ltd.; trade name: Advancell EM-503) (20 parts bymass with respect to 100 parts by mass of the adhesive resin) were eachmixed, and the solid content concentration was adjusted to 30% withethyl acetate to prepare an adhesive coating solution B4.

<Adhesive Resin Coating Solution B5>

100 parts by mass of the adhesive resin solution SB2 and 1 part by massof an ester-based cross-linking agent (manufactured by Mitsubishi GasChemical Company, Inc., solid content concentration 100%, Tetrad-C) wereeach mixed, and the solid content concentration was adjusted to 30% withethyl acetate to prepare an adhesive coating solution B5.

<Adhesive Resin Coating Solution B6>

100 parts by mass of adhesive resin solution SB2, 2.25 parts by weightof a polymerized rosin ester-based tackifier (manufactured by ArakawaChemical Industries, Ltd.; trade name: Pensel D-125) (5 parts by masswith respect to 100 parts by mass of the adhesive resin), 1.2 parts bymass of an epoxy-based cross-linking agent (manufactured by MitsubishiGas Chemical Company, Inc., solid content concentration 100%, Tetrad-C)(2 parts by mass with respect to 100 parts by mass of the adhesiveresin), 9 parts by mass of heat-expandable microspheres (manufactured bySekisui Chemical Co., Ltd.; trade name: Advancell EM-503) (20 parts bymass with respect to 100 parts by mass of the adhesive resin) were eachmixed and the solid content concentration was adjusted to 30% with ethylacetate to prepare an adhesive coating solution B6.

Example 1

The adhesive coating solution A1 was coated on a polyethyleneterephthalate (PET) film (thickness 38 μm), which is a base materiallayer, and then dried to form the adhesive resin layer (A) with athickness of 10 μm. Then, the adhesive coating solution B1 is coated onthe surface of the PET film on the opposite side to the adhesive resinlayer (A) via a separator and dried to form an uneven absorption layerwith a thickness of 20 μm, then an adhesive resin layer (B) with athickness of 25 μm formed from the adhesive coating solution B2 wasprovided thereon to obtain an adhesive film having the adhesive resinlayer (B). The adhesive resin layer (B) was formed by a method forforming the layer on a separate separator and transferring the layeronto the uneven absorption layer.

The following evaluation was performed on the obtained adhesive film.The obtained results are shown in Table 1.

Example 2

An adhesive film was obtained in the same manner as in Example 1 exceptthat the adhesive coating solution B3 was used instead of the adhesivecoating solution B1 and the adhesive coating solution B4 was usedinstead of the adhesive coating solution B2.

The following evaluation was performed on the obtained adhesive film.The obtained results are shown in Table 1.

Comparative Example 1

An adhesive film was obtained in the same manner as in Example 1 exceptthat the adhesive resin solution B5 was used instead of the adhesivecoating solution B1 and the adhesive coating solution B6 was usedinstead of the adhesive coating solution B2.

The following evaluation was performed on the obtained adhesive film.The obtained results are shown in Table 1.

<Evaluation>

(1) Measurement of Integrated Tacking Force Values F_(2.5) and F₃₀

Using a tacking tester TAC-II manufactured by RHESCA, under theconditions of a probe load of 100 gf and a probe pushing speed of 120mm/min, a probe was pressed for 60 seconds on the adhesive resin layer(B) of the adhesive films obtained in the Examples and ComparativeExamples. Next, the tack strength (gf) was measured at a testtemperature of 130° C. and test speeds of 2.5 mm/min and 30 mm/min,respectively. Here, the measurement time was set on the horizontal axisand the tack strength (gf) was set on the vertical axis, and theintegrated values were calculated respectively from the point where thetack strength started to rise from 0 to the point where the tackstrength returns to 0 again, and the obtained values were set to F_(2.5)[gf/sec] and F₃₀ [gf/sec], respectively.

(2) Position Shifting of Electronic Components in Sealing Step

The adhesive resin layer (B) side of the adhesive films obtained inExamples and Comparative Examples was bonded onto a stainless steelplate (ϕ310 mm, thickness 1.5 mm) for compression molding, semiconductorchips with a size of 5.0 mm square as electronic components were mountedand adhered on the adhesive resin layer (A) of the adhesive film so asto be in a grid pattern with an interval of 2.0 mm to obtain astructure.

Next, using a compression molding machine, a plurality of semiconductorchips on the adhesive resin layer (A) were sealed by compression moldingwith a liquid epoxy resin-based sealing material (manufactured by NagaseChemtex Corp., trade name: T693/R4212-2C) to obtain a structure in whicha sealing resin wafer (ϕ300 mm, thickness 0.5 mm) was formed on astainless steel plate.

Next, the position shifting of the electronic components was evaluatedbased on the following criteria.

No shifting: no position shifting of the semiconductor chip was visuallyobserved

Shifting: position shifting was visually observed in at least part ofthe semiconductor chip

(3) Heat Peelability after Sealing Step

The adhesive resin layer (B) side of the 10 cm×10 cm adhesive filmobtained in the Examples and Comparative Examples was pressed at apressure of 0.5 MPa and bonded on a mirror-finished stainless steelplate (SUS304BA sheet) having a length of 10 cm×width of 10 cm×thicknessof 1 mm. Next, the obtained structure was subjected to a heat treatmentat 140° C. for 60 minutes to stabilize the adhesive force of theadhesive resin layer (A) and the adhesive resin layer (B). Next, thestructure was cooled to room temperature.

Next, after heating the structure on a hot plate at 190° C. for 2minutes, the adhesive film was peeled from the stainless steel plateunder conditions of 23° C. and a tensile speed of 300 mm/min, and the180° peel force was measured.

The possibility of heat peeling the adhesive film from the stainlesssteel plate was evaluated based on the following criteria.

Possible: 180° peel force of less than 0.5 N/25 mm

Not possible: 180° peel force of 0.5 N/25 mm or more

TABLE 1 Position shifting F_(2.5) F₃₀ of semiconductor Peeling [gf/sec][gf/sec] chip possibility Example 1 3.9 14.1 No shifting PossibleExample 2 3.3 18.2 No shifting Possible Comparative 0.8 5.6 ShiftingPossible Example 1

In the Examples using an adhesive film having an integrated tackingforce value (F_(2.5)) of 1.0 gf/sec or more and an integrated tackingforce value (F₃₀) of 7.0 gf/sec or more, no position shifting of thesemiconductor element was observed in the sealing step. Thus, it isunderstood that the adhesive films of Examples were able to suppress theposition shifting of the electronic component in the sealing step.

On the other hand, in Comparative Examples using an adhesive film havingan integrated tacking force value (F_(2.5)) of less than 1.0 gf/sec andan integrated tacking force value (F₃₀) of less than 7.0 gf/sec, theposition shifting of the semiconductor element was observed in thesealing step. Thus, in the adhesive film of the Comparative Examples, itis understood that position shifting of the electronic component wasgenerated in the sealing step.

This application claims priority based on Japanese Patent ApplicationNo. 2018-061342 filed on Mar. 28, 2018, and all of the disclosurethereof is incorporated herein.

The invention claimed is:
 1. An adhesive film comprising: a basematerial layer; an adhesive resin layer (A) provided on a first surfaceside of the base material layer; and an adhesive resin layer (B)provided on a second surface side of the base material layer and inwhich an adhesive force is decreased by an external stimulus, wherein,as measured by method 1, an integrated tacking force value (F_(2.5)) ofthe adhesive resin layer (B) is 1.0 gf/sec or more at a test speed of2.5 mm/min and a test temperature of 130° C., and an integrated tackingforce value (F₃₀) of the adhesive resin layer (B) is 7.0 gf/sec or moreat a test speed of 30 mm/min and a test temperature of 130° C.,(method 1) using a tacking tester, a probe is pressed on the adhesiveresin layer (B) for 60 seconds under conditions of a probe load of 100gf and a probe pushing speed of 120 mm/min, then, at a test temperatureof 130° C., tack strengths (gf) are respectively measured at test speedsof 2.5 mm/min and 30 mm/min, a measurement time is set as a horizontalaxis and the tack strength (gf) is set as a vertical axis, integratedvalues are each calculated from a point where the tack strength startsto rise from 0 to a point where the tack strength becomes 0 again, andthe calculated values are respectively set as F_(2.5) and F₃₀.
 2. Theadhesive film according to claim 1, wherein the adhesive film is usedfor temporarily fixing an electronic component when the electroniccomponent is sealed with a sealing material in an electronic devicemanufacturing step.
 3. The adhesive film according to claim 1, whereinan adhesive force of the adhesive resin layer (B) is decreased byheating at a temperature over 150° C.
 4. The adhesive film according toclaim 3, wherein the adhesive resin layer (B) includes at least oneselected from a gas generating component and a heat-expandablemicrosphere.
 5. The adhesive film according to claim 1, wherein acontent of at least one selected from a gas generating components and aheat-expandable microsphere in the adhesive resin layer (A) is 0.1% bymass or less when an entire adhesive resin layer (A) is 100% by mass. 6.The adhesive film according to claim 1, wherein the adhesive resin layer(A) includes a (meth)acrylic adhesive resin.
 7. A method formanufacturing an electronic device comprising at least: a step (1) ofpreparing a structure having the adhesive film according to claim 1, anelectronic component attached to the adhesive resin layer (A) of theadhesive film, and a support substrate attached to the adhesive resinlayer (B) of the adhesive film; a step (2) of sealing the electroniccomponent with a sealing material; a step (3) of peeling the supportsubstrate from the structure by decreasing an adhesive force of theadhesive resin layer (B) by applying an external stimulus; and a step(4) of peeling the adhesive film from the electronic component.
 8. Themethod for manufacturing an electronic device according to claim 7,wherein the sealing material is an epoxy resin-based sealing material.